1.4. Domain and Range http://www.ck12.org
1.4 Domain and Range
Here you will refine your understanding of domain and range from Algebra 2 by exploring tables, basic functions
and irregular graphs.
Analyze means to examine methodically and in detail. One way to analyze functions is by looking at possible inputs
(domain) and possible outputs (range). Which of the basic functions have limited domains and why?
Watch This
MEDIA
Click image to the left for use the URL below.
URL: http://www.ck12.org/flx/render/embeddedobject/57855http://www.youtube.com/watch?v=FtJRstFMdhA James Sousa: Determining Domain and Range
Guidance
Domainis the possible inputs to a function. Many functions allow any kind of numbers to be inputted. This includes
numbers that are positive, negative, zero, fractions or decimals. The squaring functiony=x^2 is an example that has
a domain of all possible real numbers. Three functions have very specific restrictions:
The square root function:y=√x
Domain restriction:x≥ 0
This is because the square root of a negative number is not a real number. This restriction can be observed in the
graph because the curve ends at the point (0, 0) and is not defined anywhere wherexis negative.
The logarithmic function:y=lnx
Domain restriction:x> 0
The log function is only defined on numbers that are strictly bigger than zero. This is because the logarithmic
function is a different way of writing exponents. One property of exponents is that any positive number raised to any